There are many, many realizations that arise, as one moves from a city of 50,000, to a city of 10,000,000.

One is that having a smartphone is not merely optional. It’s a requirement.

Directions. Train schedules. Nearby restaurants. Subway routes. Cabs. Your smartphone is your modern day survival kit for living in the big city.

Here are the most commonly used “tools” in my mobile survival toolkit:

Google Maps – the most used app on my phone. Invaluable for locating the nearest subway station, best route to get from point A to point B, and for just simply finding out where in the heck I am.

Uber – while the mark of a true urbanite is their mojo in hailing a cab, with Uber even a n00b can get around anywhere in the big city… for a price, natch. Sometimes very pricey during “surge pricing”, there is still no better way of getting door-to-door in the City. Uber is a close second in my list of “must haves” in your survival kit.

MyTix – if you grab the train from Garden State, the New Jersey Transit mobile app MyTix is an absolute must have. Makes it super easy to buy, and store your train tickets. Plus, when you pay a $5 premium for buying your ticket (cash only) on the train, it can be a lifesaver (just make sure to keep your phone charged). Which leads me to…

Charger – my iPhone 5S battery is totally shot. Which means that by the time I ride the Q train from Herald Square to Avenue J, there’s more than a fair chance that my battery is well on it’s way to being dead. That’s why I always carry a spare charger, to plug in where, and when, I can. (Yeah, yeah. I need a new phone. Soon.)

So – What did I miss?

Tell me your essential smartphone survival tips, in the comments below.

Go, and be you.